1. Field of the Invention
The present invention generally relates to battery operated tools and appliances and more specifically to apparatus and methods for dissipating heat from heat-producing elements in a compact battery powered device, for controlling operating modes of the device depending on the type of battery used to power the device, and for programming the selection by the user of operating functions.
2. Background of the Invention and Description of the Prior Art
Battery powered tools and appliances have become more versatile and powerful as a result of improvements in battery technology, in the technology of battery powered devices, and in the manufacturing processes used to manufacture and assemble such devices. In particular, more powerful devices are accompanied by the need for more efficient removal of heat from the heat-producing components such as solid state devices, motors, light sources, and the like. This requirement to remove the heat produced by these components becomes more pronounced as products using batteries become smaller and more compact. Even with less heat being produced in smaller devices, components will still have a longer lifetime in general if they are permitted to operate in a cooler environment. In some prior art handheld devices heat produced internally is conducted to a metal housing to be radiated into the surroundings. However, the heating of the housing, which is usually the handle of the device or is otherwise handled by the user, may, in the least, risk discomfort to the user and or improper handling of the device while in use. Thus there is a need for more efficient ways to conduct heat away from heat sources enclosed in compact housings typically used in handheld tools and appliances.
As mentioned above, battery powered tools and appliances have become more versatile and powerful as a result of improvements in technology. In a typical battery powered device, a single type of battery is selected to power the device based on the particular functional needs of the powered device, the current and voltage characteristics of the battery, its size, cost, etc. Heretofore, the ability to interchange batteries or battery packs of differing types or chemistries in the same device has been unavailable. This inability to interchange batteries or battery packs limits the versatility of being able to adapt the device to particular circumstances of use in specific applications. In light duty cases, one type of battery may be most efficient, whereas in heavy duty applications of the same device may require a different type of battery. In other cases a primary battery may be sufficient whereas a secondary or rechargeable battery may be preferred. Further, even different battery chemistries might be used in the same product to advantage in some types of product. With the availability of various battery chemistries of both primary and secondary cells, and the ability of certain handheld tools and appliances to operate in several different modes in a single device, it would be desirable if different types of batteries could be used interchangeably in the same product.
Typically, each instance a new function is added to a tool or appliance requires an additional control to operate it, or at least to combine the control function of the new feature with a control button, knob, or lever provided for an existing feature. Often this requires some practice to use or worse, challenges the dexterity of the user. What is needed is a way to reduce a control action to a simple movement that can be interpreted by intelligence in the device. For example, one of the reasons battery powered tools and appliances have become more versatile functionally is the availability of low cost microcontrollers operable by executable programs. Such controllers can enable removing substantial amounts of circuitry, mechanical control elements, while providing enhanced operating versatility. Accordingly, it would be an advantage to users if battery operated tools and appliances such as handheld lamps, drills, screw drivers, blowers, and the like could be provided with both greater functionality and greater simplicity of operation together in one device.